docs: def task_done(self, task_id, result):
          """Set the tasks result and run the callback."""
          try:
              task = self.tasks.pop(task_id)
          except KeyError:
              return  # result of previously timeout Task
          else:
              if task.future.cancelled():
                  task.set_running_or_notify_cancel()
              elif isinstance(result, BaseException):
                  task.future.set_exception(result)
              else:
                  task.future.set_result(result)
  
              self.task_done_callback()